homeostasis

homeostasis

[ho″me-o-sta´sis]

the tendency of biological systems to maintain relatively constant conditions in the internal environment while continuously interacting with and adjusting to changes originating within or outside the system. See also balance and equilibrium. adj., adj homeostat´ic. The term is considered by some to be misleading in that the word element-stasis implies a static or fixed and unmoving state, whereas homeostasis actually involves continuous motion, adaptation, and change in response to environmental factors.

It is through homeostatic mechanisms that body temperature is kept within normal range, the osmotic pressure of the blood and its hydrogen ion concentration (pH) is kept within strict limits, nutrients are supplied to cells as needed, and waste products are removed before they accumulate and reach toxic levels of concentration. These are but a few examples of the thousands of homeostatic control systems within the body. Some of these systems operate within the cell and others operate within an aggregate of cells (organs) to control the complex interrelationships among the various organs.

ho·me·o·sta·sis

(hō'mē-ō-stā'sis, -os'tă-sis), Although the principal stress correctly falls on the third syllable in this word, the pronunciation homeosta'sis is more usual in the U.S. Do not confuse this word with hemostasis.

1. The state of equilibrium (balance between opposing pressures) in the body with respect to various functions and to the chemical compositions of the fluids and tissues.

2. The processes through which such bodily equilibrium is maintained.

[homeo- + G. stasis, standing]

homeostasis

/ho·meo·sta·sis/ (-sta´sis) a tendency to equilibrium or stability in the normal physiological states of the organism.homeostat´ic

homeostasis

(hō′mē-ō-stā′sĭs)

n.

A state of equilibrium, as in an organism or cell, maintained by self-regulating processes: The kidneys maintain homeostasis in the body by regulating the amount of salt and water excreted.

ho′me·o·stat′ic(-stăt′ĭk) adj.

homeostasis

[hō′mē·əstā′sis]

Etymology: Gk, homoios + stasis, standing still

a relative constancy in the internal environment of the body, naturally maintained by adaptive responses that promote healthy survival. Various sensing, feedback, and control mechanisms function to effect this steady state. Some of the key control mechanisms are the reticular formation in the brainstem and the endocrine glands. Some of the functions controlled by homeostatic mechanisms are heartbeat, hematopoiesis, blood pressure, body temperature, electrolytic balance, respiration, and glandular secretion. homeostatic,adj.

homeostasis

Physiology The dynamic constancy of the internal environment; the self-regulating biologic processes that maintain an organism's equilibrium; the ability to maintain a constant state under various conditions of stress

ho·me·o·sta·sis

(hō'mē-ō-stā'sis)

1. The state of equilibrium (balance between opposing pressures) in the body with respect to various functions and to the chemical compositions of the fluids and tissues.

2. The processes through which such bodily equilibrium is maintained.

[G. homoios, similar, + stasis, a standing, fr. istēmi, to stand]

homeostasis

The principle of self-regulating information feedback by which constant conditions are maintained in a biological system such as the human body. Homeostasis is essential to life and applies to thousands of bodily parameters. Some of the more obvious examples are temperature regulation, blood acidity control, blood pressure control, heart rate, blood sugar levels and hormone secretion.

homeostasis

the maintenance by an organism of a constant internal environment; an example is the regulation of blood sugar levels by insulin. The process involves self-adjusting mechanisms in which the maintenance of a particular level is initiated by the substance to be regulated. See also FEEDBACK MECHANISM.

Homeostasis

The tendency of a family system to maintain internal stability and resist change.

homeostasis (hō´mēōstā´sis),

n the tendency of biologic tissues and processes to maintain a constancy of environment consistent with their vitality and well being. For cells to maintain their stability or equilibrium, the cell membranes must be in continuous interaction with both the internal (intracellular) environment and the external (extracellular) environment. When the equilibrium of any component is disturbed, the interaction permits automatic readjustment by giving rise to stimuli that result in restoration of the equilibrium.

homeostasis

a tendency of biological systems to maintain stability while continually adjusting to conditions that are optimal for survival.

Homeostatic mechanisms are necessary for the body to regain its balance when disease or injury occurs and to maintain that balance if it is to remain healthy.

The author's main point: It can be reasonably argued that (a) improvement in insulin homeostasis with integrative therapies helped achieve the goal of satisfactory tumor-control without surgery, radiotherapy, and hormone therapies; and (b) control of the malignant lesion without surgery, radiotherapy, and hormone therapies increased the probability of improving the status of insulin homeostasis.

In spite of the absence of this pathway, what is revealing is that there is no loss of regulation in response to even exogenous insulin, as both HGP and systemic glucose homeostasis are found to be normally controlled in TLKO mice.

Loss of osseous homeostasis in a patient with normal x-rays reflects the pathophysiologic effect of the living bone at a time before irreversible structural changes have occurred, preceding degenerative joint disease and structural failure.

Ultimately, it will be argued that the components and attending processes of an organism must be considered as living, emergent phenomena because of the way in which the components are organized to maintain homeostasis of the organism at the various levels in the organismic hierarchy.

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